Hi and hello from Indy and problems with a 300D - Page 2 - PeachParts Mercedes-Benz Forum

bricktron · #16 02-27-2013, 09:32 PM

i think you can test the installation without actually running the GP circuit by checking the resistance to ground at each plug. whatever the correct resistance is (something about 0.7 ohms), i would expect to measure 5x that at the first plug, 4x that at the second plug, and so on.

Diesel911 · #17 03-01-2013, 02:24 AM

Quote:

Originally Posted by bricktron

i think you can test the installation without actually running the GP circuit by checking the resistance to ground at each plug. whatever the correct resistance is (something about 0.7 ohms), i would expect to measure 5x that at the first plug, 4x that at the second plug, and so on.

Are you speaking of the Loop/Filament Type Glow Plugs or the Adapter Pencil Type Glow Plugs that He has not installed yet.

The Loop/Filament type Glow Plugs are not normally tested like that because they are not grounded to the Cylinder Head in threaded area of the Glow Plugs like the Pencil Glow Plugs (and Spark Plugs) are.

All of the Loop/Filament type Glow Plugs are grounded to the Cylinder Head by the used of the short Ground Strap at the front of the Series of Glow Plugs wired together.

The Pencil Type Glow Plugs can be tested as you have said.

Maexle · #18 03-01-2013, 08:48 AM

i should receive the Bosch 80035 pen style glow plugs today and then i am going to wire them parallel. Anything special i have to take care of ?

vstech · #19 03-01-2013, 09:03 AM

autolight plugs SUCK!

notice that several of your zigzag resistor wires are angled, they should be installed so they are straight across to the next plug.
I like to set the feed wire on the inner connector, and the resistor zigzags on the outers.

also, notice you have the wire on top of the spacer under the insulator in the #3 plug, this bypasses the plug entirely, and raises the voltage to the other plugs. I bet you burned out #4 and 5 right? (closest to the firewall)

Maexle · #20 03-01-2013, 09:20 AM

Quote:

Originally Posted by vstech

autolight plugs SUCK!

notice that several of your zigzag resistor wires are angled, they should be installed so they are straight across to the next plug.
I like to set the feed wire on the inner connector, and the resistor zigzags on the outers.

also, notice you have the wire on top of the spacer under the insulator in the #3 plug, this bypasses the plug entirely, and raises the voltage to the other plugs. I bet you burned out #4 and 5 right? (closest to the firewall)

Just took them out, yes, #5 (closest to the firewall) is burned.

Maexle · #21 03-01-2013, 09:28 AM

The one to the right is the plug # 3 it looks different than the other ones, but i guess it's insulated the same way, isn't it ?

Maexle · #22 03-01-2013, 09:42 AM

Quote:

Originally Posted by vstech

autolight plugs SUCK!

notice that several of your zigzag resistor wires are angled, they should be installed so they are straight across to the next plug.
I like to set the feed wire on the inner connector, and the resistor zigzags on the outers.

actually only the first one (form the firewall) is angled, i did wire it just like it showed on a diagram and pictures i found.

Is this wrong?

vstech · #23 03-01-2013, 09:45 AM

I don't think so. it looks like that one is a grounded loop plug... I'd take it back to the store and get a refund.
ohm the plate to the threaded body and see if it's insulated. all the plugs should be stamped with a voltage on them. what's that one rated for?

Quote:

Originally Posted by Maexle

The one to the right is the plug # 3 it looks different than the other ones, but i guess it's insulated the same way, isn't it ?

vstech · #24 03-01-2013, 09:48 AM

if it is insulated from ground, the angle of the resistor wire and the oddity with the insulators likely caused the short to the center stud.

Maexle · #25 03-01-2013, 10:15 AM

it's insulated , i measured terminal to shell:

NGK - *Testing glow plugs

Diesel911 · #26 03-01-2013, 11:56 AM

Quote:

Originally Posted by Maexle

it's insulated , i measured terminal to shell:

NGK - *Testing glow plugs

The Adapter Glow Plugs you orderd from Advanced Auto can be teste as in the Ariticle.
The Loop/Filiment Plugs are different and do not ground through the threaded area of the Glow Plug Body.

In the Pic the central tube is insulated from the outer threaded tube. If enough Carbon builds up on the red circled areas it can ground the Plug and burn the Loop/Filiment.
If you remove the wires and the Insulator you can test the Plug with an Ohm Meter or a battery powered Test Light for an open circuit at by putting the probes on the Stud at #7 and #3 the outer washer where the red arrow points to.
If the Loop is burned you will show infinity on the Ohm Meter and you Battery Powered Test Light will not light up.

If the loop is good you should show resistance on the Ohm Meter;' but, I don't know how many Ohms is normal.

It is more normal to test them for Voltage with all the Wires connected. As you go down the line from back to front if one Plug has No voltage going into it than the Plug behind or the Wiring benind it is messed up.

Maexle · #27 03-01-2013, 02:50 PM

UP AND RUNNING...yeaaah....Bosch 80035 pen style plugs and wired parallel and the baby starts like a champ.....

Maexle · #28 03-01-2013, 02:51 PM

Thank you guys sooo much for the quick responses, i will have a lot more questions in the near future.....

THANKS ALL of you !!

Maexle · #29 03-02-2013, 09:15 AM

It was cold this morning and the baby fired right up.....awesome..... !!

BTW: brought the Autolite loop style glow plugs back to O'reilly's, showed them the burned ones and had a little "chat" with the store manager and got a full cash refund.

Thanks all.....